Copper oxide cell



Patented Dec. 1, 1931 UNlTED STATES PATENT OFFICE warm 1.. Emma, or woomwar, am) EDMUND n. mom or warrant,

' oommc'rrou'r COPPER OXIDE CELL No Drawing.

This invention relates to copper oxide cells and it comprises an electric cell of an ordinary type having an alkaline electrolyte and utilizing copper oxide as a depolarizer, sai

cell containlng a small amount of an iodid or of an iodin compound and having a lower shelf loss or longer shelf life; all as more fully hereinafter set forth and as claimed.

The most reliable type of primary cell for closed circuit work is a cell using copper oxide as a depolarizer with a caustic soda electrolyte; this kind of cell being sometimes known as the Lalande type. The opposing poles are zinc and copper and copper oxide as a body or .5 as a mass of fragments is used as a depolarizer. Sometimes the depolarizer is largely cuprous oxide, sometimes it is largely cupric. Unfortunately these cells are subject to rapid deterioration on standing on open circuit; a

deterioration which is usually called shelf loss. This is a source of annoyance in many applications of these copper oxide cells and particularly where use of current is intermittent or discontinuous, as in telegraphy 26 and telephony.

While copper oxide is fairly insoluble in caustic soda solutions it is not absolutely so, and with time on open circuit copper goes into the electrolyte in solution or colloidal 30 suspension, or both. And with a cell of this type standing on open circuit the internal resistance of the cell increases, which decreases the efiiciency of the cell. Whether this increase in internal resistance is due to the action of the caustic soda solution on the depolarizer or to the fouling of the zinc with recipitated copper, or both, is not definitely own and it is immaterial for the present purposes.

Application filed April 22,

That the solution does act on the 1830. Serial No. 8,411.

It is an object of the present invention to provide a standard type cell, that isa cell which will pass the regular commercial specifications and which nevertheless has a lower shelf loss; that is, is adapted to stand longer on open circuit without deterioration than is the case with the ordinary cells. This object is accomplished in the present invention by providin a small quantity of iodin,

an iodid or an io in compound in the system.-

tions for the caustic soda used'in this tygg cell generally specif that this material free from sulfur. t is obvious therefore that the iodin compound usedv in our invention should be sulfur-free.

Some types of cells are customarily put on the market in a dry condition, the cell containing caustic soda in dry form and a mineral oil intended to act as a floating cover to the electrolyte in operation. Upon addition of water the cell'is ready for operation.

Under the present invention iodin or an iodid may also be present in some dry form. Dry sodium iodid may be added to the caustic soda in assembling the cell; or a ellet of the dry iodid may be added in assem lage. The cop-- per oxide may be'treated with a solution of iodin or an iodid and dried, or the depolarizing body may be fumed withelemental iodin. Either treatment probably forms some cuprous iodid in the depolarizer. Sodium or 0- tassium iodid or any other convenient io in compound may be ground together with the caustic soda. It is possible to mix iodid with fused caustic soda prior to solidification.

The particular way in which the iodin com pound gets into the system is not here particularly material. 7

As to the nature of the actions oecurrin because of the addition of iodin or iodi nothing is known; it is sufiicient here to note beena the fact of an improvement in the operation of the cell. Iodin increases the efiiciency of the cell on intermittent work so that its capacity on this kind of service is tactically equal to the ordinary cell on continuous discharge; a condition that hertofore has never reached by a cell of the copper oxide type. 11 the presence of iodin, the regularity of action is increased and particularl as regards the depolarizer in which reduction goes on smoothly and uniformly without reoxida'-' tion of the copper formed in the cell action. Our invention therefore greatly increases the fiellld of use or of adaptability of this typeof ce An addition of iodin is as operative with an electrolyte of caustic potash or of caustic potash containing lithia, as with caustic soda.

What we claim is:

1. Acell of the usual Lalande type having an alkaline electrolyte and containing a small proportion of an alkaline metal iodid.

2; A cell of the usual Lalande type having an alkaline electrolyte and containing a smallproportion of sodium iodid.

3 A cell of the usual Lalande type having an alkaline electrolyte free from sulfur compounds and containing a small proportion of iodin. a

4. A cell of the usual Lalande type having an alkaline electrolyte and containing a small proportion of cuprous iodid.

5. A cell of the usual Lalande type having an alkaline electrolyte free from sulfur compounds, said electrolyte containing a small proportion of a sulfur-free iodin compound.

In testimony whereof, we have hereunto affixed our signatures. v

MARTIN L. MARTUS. EDMUND H. BECKER. 

